Blow-out preventer



ET AL 1,836,506

BLOW-OUT PREVENTER Dec. 15, 1931.

Filed Nov. 12,

192' 2 Sheets-Sheet l Y $0 5 2 M O M mw W 3M 5 w 1931. c. A. RASMUSSEN ET AL ,506

BLOW-OUT PREVENTER (77:57?! ,4 Fan-maiden My/l am 3} -7 Patented Dec. 15, 1931 UNITED STATES PA OF cnns'rnn A. RASMUSSEN, or Lone amen, AND WILLIAM AL 'rnou'r, or 1.05 ANGELES,

cams-01mm stow-our ranvnnrnn Application filed November 12, 1927. Serial No. 232,749. 1

Our" invention has to do with the oil well drilling industry, and is embodied in a blowoutpreventer which 0 erates automatically to seal the upper end 0 an oil well when the exigency arises.

To assist in pointing out the advantages of this invention a short description of the art will be' given. In the art a casing is cemented in the wellsome time before the oil formation is penetrated, and a blow-out preventer is attached to the upper end thereof so that the well may be sealed in case the formation has a high pressure. The bit is then lowered through the casing and the formation is penetrated. In case of a high pressure in .the formation it is necessary to close the blow-out preventer very quickly. The well-known blow-out preventer, commonly termed a doodle'bug in the oil fields, is manually operated. In some fields, particularly in parts of Texas, the well blows in without any warning whatever. When no warning is given it is impossible to close the blow-outpreventer because the flow of oil, gas, and sand eats away the closing parts of the blow-out preventer so that they will not effectually seal the well, and because when the well is flowing the conditions thereat are imminently dangerous for the worker. The results of a well getting out of control is that there is considerable property lost and very often injury to workmen. To overcome the present disadvantages to well-known blowout preventers, our invention provides for the closing of the sealing members automatically by fluid presure which is always available at the well. The operation is such that the sealing members may be almost instantly closed around the drill pipe without the presence of a workman at the blow-out preventer.

A further provision of the invention is that the blow-out preventer may be either manually or automatically operated.

To obviate the necessity of maintaining a fluid pressure at the well for operating the blow-out preventer after the flow of oil, sand, and gas has been stopped, our invention provides for substituting mechanical means in lieu of fluid means for holding the sealing members without disturbing the sealing positions of them.

In the preferred embodiment of the invention illustrated herein, the sealing members are moved either by fluid pressure or by mechanical pressure. The means for supplymg the mechanical pressure on each sealin member is in the form of a lead screw whic moves axiall with each sealing member. One of the o jects of the present invention is in the provision of a means which will permit an axial movement of the lead screw when the sealing member is hydraulically moved yet at the same time provide for the advancing of the lead screw to mechanically move the sealing member attached thereto, or for mechanically holding the sealing member closed after it has been. moved into sealing position by the fluid pressure.

Other objects of this invention and the advantages accruing from it will be em hasized in the description of the preferred orm of the invention which follows:

Solely for the purpose of illustration the invention is depicted in the accompanying drawings in which Fig. 1 is an elevational view showing the blow-out preventer of the invention installed at the upper end of a well.

Fig. 2 is a vertical cross section taken through the invention.

Fig. 3 is a section taken on the line 33 of Fig. 2.

Fig. 4 is a horizontal section taken on the line 44 of Fig. 2.

Fig. 5 is an enlarged fragmentary View illustrating the mechanical advancing means of the invention.

Fig. 6 is a section taken on the line 66 of Fig. 5.

B Fig. 7 is a section taken on the line 77 of Referring in detail to the drawings and particularly Fig. 1', a water string 11 is installed in the Well, the upper end extending into a pit 12 located below the floor of the derrick 13. Extended through the water string 11 and projecting from the upper end thereof is a well casing 14. A seal is provided between the well casing 14 and the water string 11 by suitable sealing means indicated by the numeral 15 of Fig. 1. Attached to the upper end of the well casing 14 1s a blow-out preventer 16 in which the features of our invention are incorporated.

Referring particularly to Fig. 2, the blowout preventer 16 of the invention has a body 20. The body 20 has a lower projection 21 into which the upper end of the well caslng 14 is screwed and an upper projection 22 to which a top pipe 23 is secured, this top pipe 23 extending upward through the floor of the derrick 13. The body 20 provides a vertical opening 25 which is in axial alignment with the o ening of the casing 14 and the top pipe 23. rovided on opposite sides of the opening 25 and on an axis which intersects the axis of the opening 25 and extends at right angles thereto are cylinders 26. The inner ends of the cylinders 26 are in communlcation with the opening 25 but the outer ends thereof are closed by end plates 27.

Referring particularly to Figs. 2, 3 and 4, the cylinders 26 each carry a sealing member in the form of a piston 28. The pistons 28 have sliding contact with the cylindrical walls of the cylinders 26 and are provlded with suitable packing 30 to form seals in order that the fluid pressure may be maintained in the cylinders. As shown particularly well in Fig. 4, the inner ends of the pistons 28 are provided with semi-cylindrical channels 31 which are vertically extended. These semi-cylindrical channels 31 are provided with packing members 32 as shown 1n Figs. 2 and 4. The pistons 28 are adapted to move from a position entirely within the cylinders 26, as indicated by dotted lines 34 of Fig. 4, into operated or sealing posltions, as indicated by full lines in Figs. 2 and 4. When in sealing osition the pistons are adapted to grip a rill pipe 35 which is extending through the blow-out preventer 16.

The pistons 28 grip the drill pipe 35, rigidly holding it in place and forming a fluid-tight seal around 1t. The pistons are provided with sealing packers 37 which provide a seal around them and prevent well pressure from escaping by way of the cylinders 26. The pistons 28 are permitted to move from retracted into sealing positions but are prevented from rotating by means of stop pins 38 (Fig. 2) which are carried by the body 20 and extend into slots 39 of the pistons. The stop pins 38 also serve the purpose of preventing either of the pistons 28 from moving past center in event that one is moved into sealing position before the other.

Referring to Fig. 4, the outer ends of the cylinders 26 have fluid passages 40 connected t ereto. Secured to the walls forming the cylinders are branch pipes 41 which communicate with the fluid passages 40. The branch pipes 41, as illustrated in Fig. l, are connected to a main pipe 42 having a valve 43,

this main pipe 42 extendingfrom a suitable fluid source. When the valve 43 is open, fluid is supplied by the pipes 42 and 41 and the fluid passages 40 to the outer parts of the cylinders 26. The pressure of the fluid urges the pistons from retracted position into sealing position, as illustrated by the full lines in Figs. 2 and 4.

The outer ends of the pistons 28 are provided with sockets 45 in which heads 46 of stems 47 are located, the heads 46 being retained in place by plates 48 attached to the outer ends of the pistons. The stems 47 extend outward through the plates 27, being surrounded by glands 50 which provide a fluid seal. Supported by the body20 at the outer ends of the cylinders 26 are nut-supporting frames 52. In the drawings the nut supporting frames 52 are shown as being formed integral with the plates 27. As shown in Figs. 5, 6 and 7, the nut-supporting frames 52 each provide a cavity 53 which is concentric with the stem 47 which extends through it. The cavit 53 is provided with a tapered wall 54 whicli is preferably of circular cross section, as shown. At the outer end of the cavity 53 is a radial abutment face 56, and the inner end of the cavity is closed by a web 57 through which the stem 47 is extended. Carried in the cavity 53 is'a slide nut 59 consisting of nut members 60. The nutmembers 60 cooperateto provide a threaded opening 61 through which a threaded portion 62 of the stem 47 is extended. The nut members 60 have tapered faces 63 which are semi-circular in cross section and which are adapted to engage the tapered wall 54. The adjacent side faces 64 of the nut members 60 are disposed in diverging relation, as shown in Figs. 5, 6 and 7. The nut members 60 are prevented from rotating by guide pins 66 carried by the nut-supporting frames 52, which guide pins 66 extend into slots 67. Also carried by the nut-supporting frames 52 are spreader pins 68 which extend into the space between the diverging faces 64 of the nut members 60. The nut members 60 are ordinarily retained in the small end of the cavity 53 by positioning springs 69 compressed between the nut members and the web 57. When in this position the threads of the threaded opening 61 engage the threads 62 of the stem 47.

When the pistons 28 are moved inward by fluid pressure the stems 47 are moved inward therewith and the nut members 60 are moved inward by the threaded engagement of the stems therewith against the operation of the springs 69. The spreader pins 68 cause the nut members 60 to move outward so that they retain their engagements with the tapered faces 53, the nut members moving into the position shown in Fig. 2. When the nut members are in this position they have moved radially outward to such an extent that the threads of the opening 61 may disengage the threads of the stems.

When the pistons are manually operated, the stems 47 are rotated so that the engagementof the threads 62 and the threads of the opening 61 advance them inward. When the stems move inward, the pistons 28 are moved from retracted into sealing position.

When the pistons 28 have been moved into sealing positions by fluid pressure and it is desired to release the fluid ressure, mechanical pressure may be substltuted by rotating the stems 47 in the proper direct-ion. In so doing, the nuts 59 will be moved outward from the positions shown in Fig. 2 into the positions shown in Fig. 5 so that the nut members 60 engage the abutment faces 56'. After this occurs, the stems will be advanced inward so that a mechanical pressure holds the pistons 28 instead of the fluid pressure. The fluid pressure source may then be shut down.

When it is desired to withdraw the pistons 28 from sealing position, it is necessary to lock the nut members 60 in the position shown in Figs. 5, 6 and 7; otherwise they would be moved to the large ends of the cavities 53 and disengage the threads of the lead screws. The invention provides an insert block 7 0, shown in Fig. 7, which is adapted to be extended into the large end of each of the cavities 53 through side openings 71. Each insert block is provided with a slot 72 through which the stems 47 may extend. When the insert block 70 is in place, the nut members 60 cannot move 1n the cavities 53 and therefore the rotation of the stems 47 in the proper direction will cause them to move outward and to move the pistons 28 into retracted position.

A brief description of the complete operation of the blow-out preventer of this invention is as follows:

Considering that the water string 11 and thewell casing 14 have been properly secured in place and the blow-out preventer 16 of the invention has been installed as illustrated in the drawings, the drill pipe 35 and a bit, not shown, attached to the lower end thereof, are lowered to the bottom of the well and drilling operations are recommenced. When the formation bearing the oil is penetrated, it may or may not have a high pressure. If it has a high pressure, gas will first commence to flow from the top of the well and usually very soon thereafter a mixture of gas, oil-and sand will spout from the top of the well. Upon first indications of a pressure in the oil formations, a well worker will open the valve 43 which permits fluid under pressure to pass into the outer parts of the cylinders 26. The fluid pressure is such as to almost instantly force the pistons 28 into sealing position. When the pistons are in sealing position, they grip the drill pipe 35 so that the pressure in the well cannot blow it from the well, and the pistons also form a tight seal which will prevent leakage.

When the seal has been formed it may be desirable to shut down the source of fluid pressure. This may be done after a mechanical pressure for holding the pistons in sealing position is substituted for the fluid pressure. The mechanical pressure is substituted for the fluid pressure, as previously explained, by rotating the stems so that the nuts 59 are moved outward into the small parts of the cavities. 53 so that they may place a thrust on the pistons 28 by means of the stems 47.

When the pressure in the well subsides or when it is maintained under control by other meansv aside fromQthe blow-out preventer, the pistons 28 may be retracted in the cylinders 26 by inserting the insert block 70, as prevlously explained, so that the nuts are maintained in their proper engaging position with respect to the stems 47. l

The essence of the invention resides in the mechanical means for automatically locking the sealing member in sealing position after the sealing member has been moved into this position by the fluid under pressure, It is also a part of the invention to provide the mechanical means which may be substituted for the fluid means at any time without disturbing the positions of the sealing members. The unique construction of the stemoperating means or the nut means is also an important part of the invention.

lVe claim as our invention:

1. In a blow-out preventing device for use on an ,oil well, and adapted for quick closing when an exigency arises, the combination of: a body adapted for securement to the upper part of a well casing, said body having a passage therethrough in communication with the interior of the well; and closing mechamsm operable to close said passage, said mechanism including a sealing member which has a sealing position and a retracted posit1on, fluid operating means operable to apply a fiuld pressure to said sealing member in a manner to move said sealing member from retracted position into sealing position, and mechanical means for operating said sealing member, said mechanical means being adapted to automatically lock said sealing member 1n sealing position without the intervention of the human element.

2. In a blow-out preventing device for use on an oil well, and adapted for quick closing when an exigency arises, the combination of: a body adapted for'securement to the upper part of a well casing, said body having a passage therethrough in communication with the 1nter1or of the well; and closing mechanism operable to close said passage, said mechanism including a sealing member which has a sealing position and a retracted position, fluid operating means operable to apply a fluid pressure to said sealing member in a manner to move said sealin member from retracted position into sea mg position, a threaded stem connected to said sealing mem- 5 her, and split-nut means engageable with said stem and being designed to ermit said stem to move without rotation wit said sealing member'and to automatically lock said sealing member in sealin position, said sealing member being) movab e either into or from sealing position y a rotation of said stem.

In testimony whereof, we have hereunto set our hands at Los Angeles, California, this 2nd day of November, 1927. CHESTER A. RASMUSSEN.

WILLIAM A. TROUT. 

